Rolling mill

ABSTRACT

This invention has to do with a universal planetary rolling mill in which clusters of rolls are rotated to swing successive rolls into the path of the stock to be rolled.

lUIlhE 40405 WEWET fireilsrhneimler 1 lFelh, 22., 11972 {54] RUILLHNGMIULIL [72] Inventor: Erich .ll. lF. lE. lllr'etschheirlner, Buderich,[56] References Chm Germany UNITED STATES PATENTS [73] Assgneei g f gMamimm (MW, 2,932,997 4/1960 Sendzimir ..72/190 1 many 2,710,550 6/1955Senclzimir..... ..72/191 11 [22] Filed: Dec. 4, 1969 3,439,519 4/1969Gerding ..72/ 190 X [21] Appl' mzws Primary Examiner-Milton S. MehrAttorney-Norman S. Blodgett [30] [Fair-elm filpphwltlm P1401 143 @1110Dec. 7, 1960 Germany .1 1s 13 331.8 {571 ABWMCT This invention has to dowith a universal planetary rolling mill 1191, 72/249 in which clustersof rclls are rotated to swing successive rolls Klim- I into the path ofthe tock to be rolled [58] lliellall ulfiwrch ..72/194, 191, 190,198,184,

72/249 ill) Claims, 5 Drawing Figures mmmmm 1972 3mm MEH sum E OF 5PMENIEBFEB22 m2 dag sum or 5 mortars MTLIL BACKGROUND OF THE INVENTIONIt is common practice to use planetary rolling mills when largereductions are to be achieved with a single pass. The prior artplanetary rolling mills have been equipped with a support roller orlarge diameter and with a number of working rollers of smaller diameterwhich operate in one plane only. Such mills may be used for rolling ofsome metal stock, but are not usable for the reduction of blooms. Theworking of blooms in accordance with the common method requires a numberof passes to reduce the cross section in two dimensions. Especially whenlarge reductions are required, it is a disadvantage that the two rollersets for working the two dimensions cannot operate in the same planenormal to the direction of rolling. Furthermore, it has proven to be adisadvantage that, when a small feed speed is used with large crosssection, cracking takes place because of burning. Therefore, a minimumfeed of around 4 inch/second has to be maintained, which again limitsthe entrance cross section of the stock to approximately 4 inch by 4inch for the desired rolling heat and commonly used exit speed. Theseand other difficulties experienced with the prior art devices have beenobviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide arolling mill for producing substantial stock reduction without cracking.

Another object of this invention is the provision of a rolling mill forworking blooms and the like at high speed.

A further object of the present invention is the provision of a rollingmill for reducing stock as much as 9 percent without the need forsupplementary feed means.

It is another object of the instant invention to provide a rolling millfor deforming stock cross section from a large square to a small circle.

A still further object of the invention is the provision of a rollingmill for reducing blooms to a round rod without the use of a reversingdrive or discontinuous operation.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rollingmill for attenuating elongated stock having a base with two spacedvertical housings and having a plurality of frames joining the housingsand grouped around the path of stock movement. A cluster of rolls isassociated with each frame and each roll is driven about a major axissubstantially spaced from the path of the stock and also about its ownaxis. The algebraic sum of the speed of the roll due to rotation aboutthe minor axis is such as to produce a desired stock speed.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. it is a side elevational view of a rolling mill embodying theprinciples of the present invention,

FIG. 2 is a sectional view of the mill taken on the line II-II of FIG.ll,

FIG. 3 is a vertical sectional view of the mill taken in a transverseplane.

FIG. 4 is a horizontal sectional view, and

FIG. 5 is a diagrammatic view of the roll pass sequence duringattenuation of the stock.

DESCRIPTION OF THE PREFERRED EMBODIMENT achieves also a desired deptheffect. The rolling stock is fed continuously and the movable partsthemselves operate continuously. This task is brought about by aplanetary rolling mill which preferably leaves out support rolls and hasworking rolls arranged on shafts which are supported in carrier arms. Bythe use of individual carrier arms and working rolls of sufficientstability (and, therefore, of large diameter per shaft), it is necessaryto provide only three working rolls by providing the required space.Therefore, the number of roll passes is restricted to three for eachrevolution of the roller carrier. The large roller diameter, however,results in the desired depth effect and permits also the separate driveof the working rolls as well as the profiling of the rollers toinfluence the desired exit cross section in a manner which is notpossible on the known universal planetary rolling mills. The requiredoutput is achieved with a limited number of revolving working rolls andthe achieved speed in comparison to the rolling stock is very high inevery case and so prevents the danger of cracking by burning.

It was determined to be of importance that the working rolls be drivenwith opposed rotation compared to the roll carriers, so that thealgebraic sum of the linear speed of the roll due to its rotation andthat due to the motion of the roll carrier equal the desired feed speedof the rolling stock. This feed speed may be arbitrarily low, since thespeed with which the working rollers are moved in comparison to therolling stock can be selected so high that the cracking by burning isdefinitely prevented. The rotation of the working rolls and the roll carriers is brought about by one prime mover, so that the adjustedrelationship of rotation speed and consequently the automaticallyadjusted feed speed of the rolling stock is maintained at apredetermined value. It was recognized to be of advantage to divert thedrive for the working rolls from the roll carrier through a planetarygear system which is adjusted to the required basic transmission ratio.To the third member of this planetary gear system is connected a controlmotor which in troduces an additional adjustable moving component. Inthis way it is possible to adjust the feed speed of the rolling stock. Asimple design of the rolling mill results by which the roller carriersrotate within their own frames, wherein the latter are supported bystands. The stands are design as pinion housings which are driven fromone main drive shaft through universal couplings connected to theindividual frames. One stand transmits the drive to the roll carriersand the other stand provides for the transmission of the drive movementto the working rolls.

The roll carriers are each provided with a gear which shall transmit thedrive power to the working rolls. In the preferred embodiment, the gearis arranged on a shaft which lies in a tubular shaft extending from theroll carrier. The shafts are driven by gearing of variable selectiveratios and are arranged within one of the driving arms. This gear drivewith such variable gear ratios is a planetary gear train wherein thethird member is driven selectively by a control motor to permit, byintroduction of an additional moving component, the change of the outputspeed. The working rolls are provided with a profile. For theachievement of cross sections of approximately circular shape at theoutlet, this profile is designed as a symmetrically, tlat wedge-shapedrecess where the center area is rounded to a radius which corresponds tothe desired exit diameter of the stock.

Referring first to FIG. ii, the rolling mill is shown as having a basefrom which extend housing It and 2 designed as pinion housings. Thehousing 2 has a pinion 3 arranged on drive shaft 3 which engages a gear5 and, consequently, drives also a gear 6. The latter transfers movementto four gears 7. The gears 5 and 6 drive bevel gears 9 through universalcouplings It as well as the parts located within a gear housing 110.

The arrangement and design of the housing ll is similar to that thehousing 2. The gears arranged within the housing are driven by a pinionmounted on the main drive shaft M by engaging these gear wheels. Thedrive shaft M is driven by a motor (not shown). Eevel gears lib locatedwithin the gear housing litll are put into motion by the: gears in thehousing ll through universal couplings 115.

Between the housings l and 2 is arranged a planetary gear system 11whose ring gear 12 is connected to the main drive shaft 14 and itsoutput portion is connected with the shaft 3. Within the ring gear 12 ofthe planetary gear system ill and around the sun gear move planetpinions which are supported within the output portion. The planetpinions are designed for the desired gear reduction which is in a ratioof 4:1 in the preferred embodiment. The ring gear 12 is rotatablysupported and is driven by control motor 13. It has proven to be ofadvantage to use as control motor a high-speed motor withcorrespondingly lower output which is driving the ring gear 12 through areduction gear.

As can be seen in FIGS. 1 and 3, the bevel gear 9 drives a bevel gear 17located on a tubular shaft 18 extending from a roll carrier 19 andserves to rotate this roll carrier. The roll carrier is designed withthree pair of fork-shaped carrier arms 20 in which are mounted shafts 21on which are arranged the live rolls. A bevel gear 16 is driven by theuniversal coupling 15 and engages the bevel gear 23 which is mounted ona shaft 24 lying in the tubular shaft 18 and carries a gear 25. The gear25 engages three gears 26 mounted on shafts 21 and so is able to drivethe live rolls 22. A roll carrier 19 lies within each frame 27. Theseframes each contain one of the gear housings l and are supported byshoulders 28 extending from the housings l and 2. The rolling stock orworkpiece 29 to be reduced is introduced through a front opening in thehousing I through a ring-shaped recess in which is supported a gearwheelcentered on a hollow shaft and the shoulder 28; the rolling stock leavesthrough a corresponding opening in the housing 2.

The rolling operation brought about by the rolling mill of the inventionis explained clearly in connection with FIG. 4. The workpiece 29 has asquare shape and is introduced on the corner to move from left to right.It is to be rolled down from a dimension of 100x100 mm. to a dimensionof 30x30 mm. This does not reflect the upper limit of the dimensions;with the chosen dimensions of the mill (especially the size of the liverolls 22), the working of rolling stock of 140x140 mm. is possible, andwith increased size of the live rolls, even greater profiles could beworked.

In FIG. 4, the frames 27 are shown in section; for simplification andfor a clearer picture, the gears and the stands are omitted; alsoomitted is the roll carrier with its live rollers between the rollingstock and the observer. In the phase of operation of FIG. 4, the liveroll 32, supported by carrier arm 30 of the roll carrier 19 engages therolling stock 29 in the viewing direction. The roll is shown in anoperating position approximately at the center of the shape-reducingarea 31 of the rolling stock. The roll carriers 19, which cause theeffective force components parallel to the drawing plane, are in such aposition that the gaps between their carrier arms 20 face the stock. Theshaping area 31 is of such a width that the the live live roll 32 inworking position may pass the shaping area without being restricted bythe carrier arms of the two vertical roll carriers 19. During rotationof all roll carriers in the direction of arrows 33 to 35, the live rollpairs always alternate and are guided through the shaping area 31 ofrolling stock 29 in a manner that the live rolls of the oppositelyarranged roll carriers are always effective at the same time.

Through the separate drives of roll carriers and live rolls, which areactivated by the roll carrier 19 through universal joints 8 and 15, itis possible to synchronize the speed of the roll carriers and the liverolls in such a way that the area of the live roll which is in contactwith the rolling stock activates slow feeding. There is no danger ofcracking through burning, because the liver rolls are not onlyactivating a slow feeding, but are turning themselves within the shapingarea 31 and are guided over the rolling stock with such a high speedthat such cracking by burning is definitely prevented. Through thealternate action of the live roll areas as displaced 90 relative to eachother, the rolling stock is rolled out alternately during one cycle ofthe roll carriers. This occurs first in the horizontal direction andthereafter in the vertical direction until every one of the live rollshas taken part in the action, so that the introduced square crosssection is reduced, so that wire bars with square cross section areleaving the rolling stand considerably reduced in cross section.

The feed speed may be adjusted from the exterior of the mill for anydesired value. The resulting reduction by this different drive branchesand by the planetary gear system H is brought about in such a way that,with stationary sun gear 12, an average feed speed of the rolling stock29 is achieved. By the operation of the control motor 13 in thedirection of rotation, it is possible to increase the average feedspeed. By reversing it, the feed speed may be lowered below the averagespeed. By corresponding control of the control motor speed, any feedspeed may be introduced. With this method, it is possible to adjust theshaping procedure to the physical properties of the material of therolling stock to be rolled. By the use of higher feed speed, every passof one live roll pair results in a greater reduction and so correspondsto a greater depth effect. On the other hand, with sensitive material, alimitation in working of the material may be desired; this can beachieved by a reduction of the feed speed. The surfaces effected by thepass of one roll pair are close together within the shaping area and thecorresponding material reduction is brought about in accordance with thedesired lower working operation.

The energy consumption of the control motor is small because the motoradds only a small amount of the operating energy transmitted to the liverolls. By the use of high-speed motors and large speed reduction, only asmall space is necessary.

FIG. 5 shows a bloom 41 which is worked by the live rolls 37 driven andoperated with a universal planetary roll mill stand built in accordancewith this invention. The live rolls 37 are designed with a profile'BSwhich has the shape of a flat doublewedge recess (facing conicalsurfaces) and its root or valley 39 is rounded in such a way that itsradius corresponds to the radius of the final desired cross section.

To illustrate the continuous shaping operation, four cross sections 41to 44 are taken in the shaping zone 4th of the rolling stock; each isshown with the corresponding live rolls. The cross section 41 of therolling stock has a square shape and its corners are supported by theroot 39 of the profile 38 of the live rolls 37 and are the first to beexposed to the shaping operations. In the following cross section 12,the contact sections of the live rolls 37 and also the following pair ofrolls 45 have moved closer together and the rolling stock cross sectionis developing in the direction of an octagonal shape, wherein the fourcomers have already been rounded with the final radius. During thecontinuous pass to the area of cross section 4-3, a further shapingoccurs by which the octagonal shape is maintained, but its area islargely reduced. The final cross section 44 appears very close to thecircular shape. It is, therefore, possible not only to reduce square orrectangular rolling stock to a square or rectangular exit cross section,but also, within a wide range, to achieve selective exit cross sectionswithout abandoning the important advantage of a planetary mill, namely,the exceptional large cross section reduction available within therolling stand. The universal planetary rolling mill, therefore, issuitable where large cross section reductions are to be made within twoareas in one operation, or where only low entrance speeds are present.The larger diameter of the live rolls permits the omission of specialdrive stands, and permits the shaping operation to start evenly at thehead of the rolling stock. The introduction of the rolling stock to themill is made considerably easier. The introduction of the additionalcontrol motor permits a simple, sure, and constant determination of thedesired feed, because the control operation is concerned with only onepart of the speed and only a negligible part of the driving power isobtained from this motor.

As a consequence of the clean rolling operation, the work requirement isconsiderably small. It is possible to reduce substantially blooms andbillets in a single stand with a continuous operation to the desireddimensions without the use of an expensive and generally not fullyusable, continuously blooming train, and without operating the standswith reverse drive, and without stopping and starting large masses, asin discontinuous operation.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. it is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddescribed to secure by Letters Patent is:

l. A rolling mill for attenuating an elongated bloom or the like,comprising a. a base having two spaced, parallel housings extendingtherefrom,

b. four frames extending between the housings, the frames extendingperpendicularly to the housings and being grouped around the path of thebloom to form a boirlilre configuration,

c. a cluster of rolls associated with a roll carrier mounted on eachframe, each carrier being rotated about a major axis substantiallyspaced from the said path and each roll being entirely supported by thecarrier for rotation about its own minor axis,

cl. means driving each carrier to bring its rolls successively adjacentthe said path, and

e. means driving each roll to bring about deformation of the workpiecewhen it is adjacent the said path.

2. A rolling mill as recited in claim ll, wherein the rolls are drivenin the opposite direction to that of the carrier, so that the algebraicsum of the peripheral speed of a roll and the speed due to the rotationof the carrier is equal to the desired rate of longitudinal feed of theworkpiece.

3. A rolling mill as recited in claim li, wherein the means driving thecarriers and the means driving the rolls are operated from a main driveshaft.

i. A roiling mill as recited in claim El, wherein the main drive shaftoperates through a planetary gear system for rotation of the carriers atdifferent speeds than the rolls, and wherein the said different speed ofrotations is produced by use of a controi motor connected to theplanetary gear system.

55. A rolling mill as recited in claim il, wherein each roll is providedwith a formed groove, the groove having symmetrical double frustoconicalsurfaces with the root rounded to the radius of the desired exit crosssection of the workpiece.

ti. A rolling mill as recited in claim ll, wherein the rotation of theroll carriers about their major axes are synchronized so that rollers ofone set of opposed carriers arrive adjacent the said path at the sametime and the rollers of the other set of opposed carriers not onlyarrive at the same time, but also between the times of arrival ofsuccessive roll pairs of the said one set, so that roll pairs contactthe workpiece alternately in planes apart.

'7. A rolling mill as recited in claim ll, wherein each of the housingscontains four pinion gears connected to be driven together, wherein eachgear is connected through a spindle and universal couplings to one ofthe roll carriers.

ii. A rolling mill as recited in claim "I, wherein each roll carrierincludes a main gear rotatable about the major axis, and secondary gearsmounted on the individual rolls and in driving contact with the maingear.

9. A rolling mill as recited in claim it, wherein the main gear ismounted on the shaft which rotates within a tubular shaft fixed to theroll carrier, the two shafts being driven at different speeds, thedifference between the speeds being adjustable.

iii. A rolling mill as recited in claim 9, wherein the speeds areadjustable by virtue of a planetary gear system, having a ring geardriven by a control motor.

1. A rolling mill for attenuating an elongated bloom or the like, comprising a. a base having two spaced, parallel housings extending therefrom, b. four frames extending between the housings, the frames extending perpendicularly to the housings and being grouped around the path of the bloom to form a boxlike configuration, c. a cluster of rolls associated with a roll carrier mounted on each frame, each carrier being rotated about a major axis substantially spaced from the said path and each roll being entirely supported by the carrier for rotation about its own minor axis, d. means driving each carrier to bring its rolls successively adjacent the said path, and e. means driving each roll to bring about deformation of the workpiece when it is adjacent the said path.
 2. A rolling mill as recited in claim 1, wherein the rolls are driven in the opposite direction to that of the carrier, so that the algebraic sum of the peripheral speed of a roll and the speed due to the rotation of the carrier is equal to the desired rate of longitudinal feed of the workpiece.
 3. A rolling mill as recited in claim 1, wherein the means driving the carriers and the means driving the rolls are operated from a main drive shaft.
 4. A rolling mill as recited in claim 3, wherein the main drive shaft operates through a planetary gear system for rotation of the carriers at different speeds than the rolls, and wherein the said different speed of rotations is produced by use of a control motor connected to the planetary gear system.
 5. A rolling mill as recited in claim 1, wherein each roll is provided with a formed groove, the groove having symmetrical double frustoconical surfaces with the root rounded to the radius of the desireD exit cross section of the workpiece.
 6. A rolling mill as recited in claim 1, wherein the rotation of the roll carriers about their major axes are synchronized so that rollers of one set of opposed carriers arrive adjacent the said path at the same time and the rollers of the other set of opposed carriers not only arrive at the same time, but also between the times of arrival of successive roll pairs of the said one set, so that roll pairs contact the workpiece alternately in planes 90* apart.
 7. A rolling mill as recited in claim 1, wherein each of the housings contains four pinion gears connected to be driven together, wherein each gear is connected through a spindle and universal couplings to one of the roll carriers.
 8. A rolling mill as recited in claim 7, wherein each roll carrier includes a main gear rotatable about the major axis, and secondary gears mounted on the individual rolls and in driving contact with the main gear.
 9. A rolling mill as recited in claim 8, wherein the main gear is mounted on the shaft which rotates within a tubular shaft fixed to the roll carrier, the two shafts being driven at different speeds, the difference between the speeds being adjustable.
 10. A rolling mill as recited in claim 9, wherein the speeds are adjustable by virtue of a planetary gear system, having a ring gear driven by a control motor. 